Efficacy of Core Stability Training on Endurance, Kinetic Chain Function, and Dynamic Balance in Soccer Players

Participants will start with a standard prone plank position on a bench supported on their elbows and feet. They must keep their head, torso, pelvis, and heels in a straight line and their elbows aligned vertically with their shoulders. While maintaining this position for 60 seconds (s), they will perform several tasks consecutively: (1) raise their right arm for 15 s, then lower it and raise their left arm for 15 seconds, then lower it down; (2) lift the right leg (in a straight position) for 15 s, then lower it and lift the left leg for 15 seconds and lower it down; (3) raise the right arm and left leg (diagonally) for 15 s and lower them down; (4) raise the left arm and right leg (diagonally) for 15 s and lower them down; (5) keep the prone plank position for 30s. Then, participants will repeat the same steps (1-5) until the prone plank position cannot be maintained.

First, participants will be asked to lie on the floor mat in a prone plank position; their feet will be apart at shoulder width. While maintaining the prone plank position with their body kept in a straight line, participants will be asked to start crossing their legs alternately as fast as possible for 15 seconds. The Assessor will start the stopwatch, pre-setted for 15 seconds when the participants start moving. The assessor will simultaneously and manually count the number of successful crosses each participant can make during those 15 seconds. A successful cross is defined as participants touching, with their moving foot, the floor at the lateral side of their stationary foot and then fully returning to the starting position.

The floor will be taped with three crossing lines. Participants will be asked to stay barefoot and to stand upright with one foot (foot of the testing limb) positioned in the middle of the grid. The most distal part of the big toe of the stance leg should be placed just at the crossroad between the three lines. The position of the stationary foot should remain constant throughout the whole testing procedure. Moreover, participants' hands shall remain on their hips throughout the test to focus on the lower limb performance. Participants will then be asked to reach as far as possible with the other limb in each of the three directions. They should touch (without weight bearing) the line where they can maximally reach by the most distal part of the big toe and return to the starting position without losing their balance. Using a tape measure, the assessor will measure and record the distance (in centimeters) reached.